asked on

Error: Cannot mak a visible winow modal (Delphi 6)

I have made automation server (DLL) and controller using delphi 6. But I have a runtime error showing "Cannot make a visible window modal" when I call function to launch a (Server) form. I know that to use showmodal, a form have to set it visible property to FALSE and formStyle = fsNormal. And I have set these properties and it is not work.

How can I fix this problem? I tried to set its properties during runtime, however it is not work. This is my code in Controller.

procedure TfrmMain.mnuMaintenanceClick(Sender: TObject);
var WorkOrderMgr : IMaintenanceWorkOrderSvr;
begin
WorkOrderMgr := CoMaintenanceWorkOrderSvr.Create;
try
if WorkOrderMgr.Login(Users1.CurrentUser.UserName,
Users1.CurrentUser.Password ,'Central',
MaintenanceDM.ADOConn.ConnectionString) then

WorkOrderMgr.LaunchUI
else
MessageDlg('Fail to login',mtError,[mbYes],0);
finally
WorkOrderMgr := nil;
end;
end;

and on Automation server.

procedure TMaintenanceWorkOrderSvr.LaunchUI;
var frmMaintenance : TfrmMaintenanceMgr;
begin
if FLoginOk then
begin
frmMaintenance := TfrmMaintenanceMgr.Create(nil);
try
frmMaintenance.UserName := FUserName;
frmMaintenance.FormStyle := fsNormal;
frmMaintenance.Visible := False;
frmMaintenance.ShowModal;
finally
frmMaintenance.Free;
end;
end;
end;

Or you could you please suggest me how to do step debugging in automation server.

soapsiam.

ASKER CERTIFIED SOLUTION

esoftbg

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SOLUTION

Pierre Cornelius

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soapsiam

ASKER

My form is local variable, how can I make a second show modal form?

soapsiam

ASKER

esoftbg
frmMaintenance can not be assigned in AutoCreate Forms as it is DLL.
I also remove "var frmMaintenance : TfrmMaintenanceMgr;" from my code.

esoftbg

Do you want to have more than one instance of TfrmMaintenanceMgr at the same time, or you need a new instance after closing the previous one ?

soapsiam

ASKER

esoftbg

I want only one instance of TfrmMaintenanceMgr. If user close a form, it is freed. And recreate again if desire.

esoftbg

You need to implement into the .DLL a method for creating and showing the Form inside it ....

take a look at:

https://www.experts-exchange.com/questions/20923641/Forms-in-DLL.html
https://www.experts-exchange.com/questions/20665112/Forms-Inside-A-Dll.html

esoftbg

https://www.experts-exchange.com/questions/20923641/Forms-in-DLL.html
https://www.experts-exchange.com/questions/20665112/Forms-Inside-A-Dll.html

and into the .DLL it will be:

//....

uses
SysUtils,
Classes,
Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

procedure ShowDllForm; stdcall;
begin
frmMaintenanceMgr :=TfrmMaintenanceMgr.Create(nil);
try
frmMaintenanceMgr.ShowModal;
finally
frmMaintenanceMgr.Release;
end;
end;

Exports
ShowDllForm;

begin
end.

SOLUTION

TheRealLoki

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soapsiam

ASKER

I have create a new form in COM Client and it can show modally. I think it might be problem by one of component may be TUsers of ToolsandComps.

soapsiam

ASKER

I don't know what causes the problem for this situation but when I open dfm file, no Visible property of form there. So, I add Visbile = True in dfm and it works. And before I add this, in object inspector its visible is false.

Thanks for all comments, so I will delete this question.

soapsiam

ASKER

I have found what is a problem for this, it is FastReport. When I made error on fastreport (script) that is on my form and exception is shown. Then a showmodal is not working. I open the DFM file and insert Visible=False. Ok, it works fine.

Thanks